I tried searching and couldnt find anything on it. Im sure its on here somewhere im just to dumb to find it . Anyone have experience with bypassing the lines that plum coolant through the throttle body. Any milage or power advantages? Thanks

 

the throttle body coolant lines are strickly there for cold temperature running. Some say by bypassing it they have noticed additional power other say no gains. The theory is the same as adding a spacer between the intake and the plenum. The cooler the intake charge is the better, at least when it's warm to hot out. I added a small ball valve on the feed side of the coolant line that way during the winter i can set it back to the factory.The throttle body was noticeably cooler and I do feel a slight power gain.

 

The coolant in the TB has one other function and that is to prevent the throttle blade(s) from freezing in the bore. This can happen even above 32 deg. Having said that I've never had it happen on the two that I bypassed here in New England. I do hook it back up for winter driving.
regards
rikard

 

Thanks for the replies. I bypassed them on an older f250 with a 302. however i swapped it from a 2wd 5spd to having a C6 and 205 tcase and the 2wd suspension got traded for a d44 and 4.56s in both ends. so idk if it helped that truck or not lol. Mechanically i can do just about everything but understanding somethings ford does eludes me. I wouldnt know why they would expect the throttle blades to freeze never heard of any other company doing tha and ive owed chevys dodges and my ford is the only one like that lol

 

I bypassed mine on my 351W. No use for them here in SW Florida. Removed the lines completely. Hasn't effected the performance one way or the other.

CS45

 

I wondered about this also-why the coolant lines for the TB-I dont see other vehicles with this feature. But then-most vehicles have their TB directly right on top middle of the intake manifold and the intake heat keeps the TB warm. But these Fords have the TB removed from the intake manifold heat and dont get the engine heat.

(I also wondered why there is dual intake throttle plates. I figured out that the long distance between the factory air cleaner assembly and the TB would cause restriction of intake air unless there were two intake air hoses and throttle plates. These EFI Fseries have more throttle plate area then the 5.0 HO Mustang.)

You can bet-Ford wouldnt go thru the expense of making,stocking,installing these coolant hoses unless their was a good reason for them. But it is interesting that the owners that have removed them havent had any trouble. But then-it may make a difference when the amibient temperature is 20F below-like it can get here in Colorado.

If anyone wants the Ford part numbers for the coolant rubber hoses -let me know.

 

My 94 Chevy Caprice SW with the LT1 has coolant going to the TB and the Impala/Caprice sites have info on bypassing those so its not just a Ford thing. The TB on the LT1 is mounted on the front of the engine away from the block like the Fords but the intake is shorter.

regards
rikard

 

The Ford shop manual says they are there to add to the performance of the engine by heating the air to vaporize the fuel better.
They have nothing to do with cold weather operation. There is no refrigeration at the throttle body like there was on the old Carburetor engines with the venturi effect.

 

Wouldnt the bypass of the IAC also have a Venturi effect possibly? And how wouldnt the ambient temperature-especially on cold start up in sub zero temperature not have an effect on cold weather operation on a remote mounted TB? And there is no fuel to vaporize at the TB of an port injection EFI engine.

If the coolant heat at the TB is necessary to warm the intake air during normal engine temperature--then any issues would be worse during extreme cold operation-I would think.

 

No venturi effect.

Yes that is why they want to heat the air going into the cylinders so the fuel will vaporize better.

The fuel will vaporize better with warm air at the port.

True and that is why they want to heat it.

 

Trying to keep the incoming air at a more constant temp may help the computer meter fuel better also, especially on the SD motors.

Rob

 

Thank you guys so much for the repies it does help shed so light on the subject.

I did forget about the LT-1s ahving it also. but i do believe the LS styles do not, cant be sure till the HD gets back in the driveway lol

 

Why wouldnt there be a venturi effect in the IAC? The venturi effect is when there is decreased air pressure because of increased air flow when air is forced to flow though a narrow passage.This would be an issue when the truck is idling in cold weather with the throttle plates completely closed and all intake air is going thru the IAC. Isnt that correct?

Partly opened throttle plates would also have a venturi effect. And this venturi effect would especially be a problem in ambient cool intake air with high humidity. The only difference between a carburetor and TB-is that the gasoline doesnt have to be vaporized in the TB and this gasoline vaporization's added cooling effect doesnt occur in the TB with port injection. But the cooling effects of the Venturi effect itself must still be involved in a remote mounted TB with port injection.


Why would it be necessary to warm the air at the port on only these Fseries using coolant heated intake air? The engine heat itself would heat the air if these trucks had a normal intake mounted and engine warmed TB.

I believe that you are actually making my original points:

1/ The remote front mounted relatively cool TB with long intake tubes makes it necessary to add heat to the TB for normal engine operation.

2/ Cold ambient weather operation is made better.

We both agree: heated intake air makes these trucks run better. And I also suspect-Ford wanted to ward off the possiblity or probability of frozen throttle plates. And the resultant legal liability.

 

There is no venturi so no venturi effect.

I am not sure you know what a venturi is.
A venturi:
http://image.chevyhiperformance.com/...uri_effect.jpg

True but you do not have the narrow passage in the throttle body. The venturi effect as in carburetors would reduce the air temp a few degrees and if you had high humidity and the temp was between 33 and 38*F ice would form and shut off the air supply to the engine. Carburetor heat was not needed below 32 or above about 39*F depending on the atmospheric pressure.

I do not think the throttle body can drop the OAT enough to form ice.

Also I did not design the air system on the Ford truck, I am just saying what the Ford shop manuals say that it is to improve performance and not for icing conditions.

 

So would an air intake that draws warn air in be better that one that draws air from outside ??....Lew